The study consists of 37 frail old subjects, age ≥ 65 sub-grouped in 17 OOM, and 20 OLM and 11 non frail controls. These subjects will be studied with positron emission tomography (PET), computed tomography (CT), magnetic resonance imaging (MRI) and spectroscopy (MRS) and ultra sounds (US). In addition functional MRI (fMRI) will be performed. Adipose tissue biopsies will be taken.